Brief Educational Workshops in Secondary Schools Trial (BESST): protocol for a school-based cluster randomised controlled trial of open-access psychological workshop programme for 16-18-year-olds.

Anxiety and depression are increasingly prevalent in adolescents, often causing daily distress and negative long-term outcomes. Despite the significant and growing burden, less than 25% of those with probable diagnosis of anxiety and depression are receiving help in England. Significant barriers to help-seeking exist in this population, with a scarcity of easily accessible, effective, and cost-effective interventions tailored specially for this age group. One intervention that has been shown to be feasible to deliver and with the promise of reducing stress in this age group is a school-based stress workshop programme for 16-18-year-olds (herein called DISCOVER). The next step is to rigorously assess the effectiveness, and cost-effectiveness, of the DISCOVER intervention in a fully powered cluster randomised controlled trial (cRCT). If found to be clinically and cost-effective, DISCOVER could be scaled up as a service model UK-wide and have a meaningful impact on the mental health of adolescents across the country.Trial registration: ISRCTN registry ISRCTN90912799. Registered with ISRCTN 28 May 2020.